Class of non-sensitizing infra-red dyes for use in photosensitive elements

Abstract

A novel class of non-sensitizing infra-red dyes derived from heptamethine dyes with indolenine nuclei is disclosed. They are useful as filter-, acutance- or antihalation dyes for photographic elements based on silver halide or for photothermographic elements.

Claims

1. Photosensitive material comprising at least one photosensitive layer and optionally one or more other non-photosensitive layer(s), characterized in that at least one of said layers contains an infra-red absorbing compound represented by following general formula:

Z represents hydrogen, or one or more substituent(s), or the necessary atoms to complete a fused-on aromatic ring,

R.sup.1 and R.sup.2 each independently represent hydrogen or lower (C.sub.1 -C.sub.3) alkyl which may be substituted,

R.sup.3 represents lower (C.sub.1 -C.sub.3) alkylene which may be substituted,

R.sup.4 represents an alkyl or aryl group which may be substituted,

each of L.sup.1 -L.sup.7 represents a methine group which may be substituted, and the substituents of which may link together to form a supplementary ring which may be substituted itself.

2. Photosensitive material according to claim 1 wherein said material is a photographic material based on silver halide.

3. Photosensitive material according to claim 1 wherein said material is a photothermographic material.

5. Photosensitive material according to claim 1 wherein said infra-red absorbing compound is incorporated in a non-photosensitive layer positioned on the same side as the photosensitive layer, but farther from the support than the photosensitive layer, and serves as a filter dye.

6. Photosensitive material according to claim 1 wherein said infra-red absorbing compound is incorporated in a non-photosensitive layer positioned between the photosensitive layer and the support, or in a backing layer, and serves as an antihalation dye.

7. Photosensitive material according to claim 1 wherein said infra-red absorbing compound is incorporated in said photosensitive layer itself, and serves as an acutance dye.